Quarterback Josh Nunes, who lost his starting job to Kevin Hogan at midseason last year, will miss all of Stanford's spring practices with an undisclosed injury, coach David Shaw said Friday.

Shaw said Nunes, who will be entering his final year of eligibility in the fall, will be wearing a sling but wouldn't specify whether the injury was to his arm or shoulder. Nunes was hurt a couple of weeks ago in "a freak occurrence" at a workout, Shaw said. "It's something that hasn't happened here. It shocked us."

While Hogan is firmly entrenched as the No. 1 quarterback, Nunes' absence will open opportunities for backups like sophomore Evan Crower and freshman Dallas Lloyd, who joined the team last fall after a two-year Mormon mission.

"It opens the door for them to show what they can do," Shaw said.

The Cardinal have a well-stocked roster as they come off a Pac-12 championship season in which they won the Rose Bowl for the first time in 41 years. They begin the first of two spring practice sessions Feb. 25 and finish the workouts with the spring game April 13 at Stanford Stadium.

Besides Nunes, two players who won't be in action in the first session are starting inside linebacker Shayne Skov and his brother, Patrick, a reserve fullback. Shayne Skov's absence is part of his punishment for a DUI arrest in January 2012. Patrick will be attending to "a family matter," Shaw said.

Cornerback Barry Browning probably will miss both spring sessions because of what Shaw called "a minor procedure."

In another development, Shaw said sophomore inside linebacker James Vaughters is being moved to the outside, where he might replace the graduating Chase Thomas, a fellow Georgian.

Still another Georgian, David Yankey, a consensus All-American at left tackle last season, is moving back to his natural position at left guard. "I don't know that there's a better puller in college football," Shaw said. "He's at least in the conversation for the best guard in the country."

The tight end competition won't involve starting fullback Ryan Hewitt, a former tight end, but it will involve two converted players, 6-foot-6, 274-pound sophomore Charlie Hopkins, who until now has been a defensive end, and current offensive tackles Eddie Plantaric and Kyle Murphy.

Freshman running back Barry Sanders, the son of the Hall of Famer of the same name, will be among several players trying to replace workhorse Stepfan Taylor. "He's lived with his name his whole life and the expectations that go with that," Shaw said. "His role will start up small but grow over time."

The surprising return of Tyler Gaffney adds experience to the mix at running back. The former minor-league baseball player had missed the camaraderie of Stanford football and told Shaw on the phone near the end of January that he wanted to come back for his senior season.

He won't join practice until the second session after he enrolls April 1, but "he'll be training this whole time, lifting and running," Shaw said. "He'll be out here all summer with the guys."